adapt to tip's error message change from "GOROOT" to "std"

.github/workflows/test.yml

@@ -91,7 +91,7 @@ jobs:
     steps:
     - name: Install Go
       env:
-        GO_COMMIT: acd8dc95833182df86831ec78e7470864bdb3b88 # 2023-05-12
+        GO_COMMIT: aeb0644bd33e67f24e2411a651ac9ff72ddc96b4 # 2023-05-19
       run: |
         cd $HOME
         mkdir $HOME/gotip

shared.go

@@ -285,7 +285,10 @@ func appendListedPackages(packages []string, mainBuild bool) error {
 			// like "arena", so older Go versions that we support
 			// do not yet have them and that's OK.
 			// Note that pkg.Standard is false for them.
+			// Note that Go 1.21 is swapping "GOROOT" for "std".
+			// TODO(mvdan): We try to list test packages like runtime/metrics_test, which always fail.
 			case strings.Contains(perr.Err, "is not in GOROOT"):
+			case strings.Contains(perr.Err, "is not in std"):
 			case strings.Contains(perr.Err, "cannot find package"):
 			}
 		}

testdata/script/help.txtar

@@ -78,7 +78,8 @@ stderr 'must precede command, like: garble -seed=random build \./pkg'
 stderr 'did you run.*instead of "garble \[command\]"'
 
 ! exec garble build badpackage
-stderr 'package badpackage is not in GOROOT'
+[!go1.21] stderr 'package badpackage is not in GOROOT'
+[go1.21]  stderr 'package badpackage is not in std'
 ! stdout .
 
 ! exec garble build ./badpackage

testdata/script/list_error.txtar

@@ -1,11 +1,17 @@
 ! exec garble build ./...
-cmpenv stderr stderr.golden
+[!go1.21] cmpenv stderr stderr-go1.20.golden
+[go1.21]  cmpenv stderr stderr-go1.21.golden
 
--- stderr.golden --
+-- stderr-go1.20.golden --
 # test/main/broken
 broken${/}broken.go:5:16: cannot use 123 (untyped int constant) as string value in variable declaration
 # test/main/imports_missing
 package test/main/missing is not in GOROOT (${GOROOT}${/}src${/}test${/}main${/}missing)
+-- stderr-go1.21.golden --
+# test/main/broken
+broken${/}broken.go:5:16: cannot use 123 (untyped int constant) as string value in variable declaration
+# test/main/imports_missing
+package test/main/missing is not in std (${GOROOT}${/}src${/}test${/}main${/}missing)
 -- go.mod --
 module test/main